Rotary switch



Feb. 24, 1970 c, w, HE T 3,497,643

' ROTARY swncn Filed April 18, 1968 2 b b b 7G 2 s 72 7 b 78 77 I, 17 18 75 'Q a INVENTOR CLARENCE WILLANS HEATH BY $206142. Wmcd Za/Wa/m ATTORNEY United States Patent O U.S. Cl. 2006 4 Claims ABSTRACT OF THE DISCLOSURE A rotary switch comprising one or more pivotally mounted contact arms adapted to be moved by a camshaped rotor into engagement with fixed contacts, a leaf spring being provided associated with each movable contact arm for biasing it into engagement with the cam surface of the rotor.

BACKGROUND OF THE INVENTION It has previously been proposed to provide a rotary switch including pivotally mounted contact arms adapted to be moved about their pivot points by the cam surface of a rotor so that the arms are moved into engagement with fixed contacts in the casing of the switch. For the correct timing of the closure of the contacts it is important that the contact arm be always in resilient abutting engagement with the cam surface of the rotor so that the arms will be pivoted when the high points of the cam surface come into contact with the arm. It is an object of the present invention to provide improved means for biasing the contact arms into engagement with the rotor.

SUMMARY OF THE INVENTION The present invention provides a rotary switch comprising a casing, a cam-shaped rotor rotatably mounted in said casing, a pivotally mounted contact arm engageable by said rotor, a fixed contact for co-operative engagement by said contact arm when said arm is pivoted by said rotor, a contact terminal pivotally supporting said contact arm and a leaf spring including a blade portion and an arcuate-shaped base portion, the blade portion extending longitudinally of the contact arm and abutting the same so as to bias it into engagement with the said rotor and the said arcuate-shaped base portion abutting said contact terminal.

The curved end portion may be formed with an extension including a concavely curved portion disposed in overlapping relation to a convexly curved part of the easing of the switch.

The blade portion of the leaf spring may be secured to the contact arm by providing an integral lug on the blade portion which engages an adjacent portion of the contact arm.

To enable the invention to be fully understood, it will now be described, by way of example, with reference to the accompanying drawings which is a side view, partly in section, of a switch according to one embodiment of the invention.

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As shown in the accompanying drawing, the switch comprises a casing including a base 1, side walls 2 and a cover 3 in which are mounted fixed contacts 4, 4a, 5, 5a, the portions of the contacts projecting into the casing being provided with contact pips b. As shown, the pips b of the contacts 4-, 4a as also those of the contacts 5, 5a. are in opposed facing relation.

Movable contact arms 6, 7, are provided having double faced contacts pips 6a, 7a at one end. At the opposite end the respective arms are formed with lugs 8, 9, pivotally supported in slots 10 in contact terminals 11. Each of the contact arms is provided with resilient means biasing the arm towards the cam surface 12 of a rotor 13. As shown, each resilient means comprises a leaf spring having a blade portion 14 extending longitudinally of and in abutment with the contact arm and attached thereto by a lug 15 bent out of the blade portion and engaging round the adjacent portion of the contact arm. The blade portion 14 has a curved end 16 bearing against the contact terminal 11 adjacent the slot. The end has an extension bent to form a nose-like projection 17 facing away from the blade 14 and directed towards a recess 18 in the side walls.

The extension also includes a concavely curved portion 19 which overlies a convexly curved portion 20, of the side walls of the casing.

The contact terminals 11 are formed with tailpieces 21 projecting outwardly of the switch casing for connection to lead wires to complete a circuit to the respective arms 6 and 7.

The fixed contacts 4, 4a, 5, 5a are also adapted to be attached to lead wires, and accordingly during the rotation of the rotor 13, when the high portions of the cam 12 engage the outwardly bent portions 22 of the arms 6 and 7 respectively, they will be displaced against the action of their respective leaf springs into engagement with the fixed contacts 4 and 5a. When the recessed or low portion of the cam is aligned with the portions 22, the arms will be positioned by the action of the leaf springs in engagement with the fixed contacts 4a, 5, and when the portion of the cam intermediate the high and recessed portion is aligned with the bent portion 22, the contact arms will be in an intermediate position out of engagement with both the fixed contacts.

While the switch illustrated and described is provided with two movable contact arms each engageable with two fixed contacts, it will be understood that the switch may include one, or more than two movable contact arms, each engageable with a single or a pair of contacts.

I claim:

1. A rotary switch comprising a casing, a cam-shaped rotor rotatably mounted in said casing, a pivotally mounted contact arm engageable by said rotor, a fixed contact arm engageable by said rotor, a fixed contact for co-operative engagement by said contact arm when said arm is pivoted by said rotor, at contact terminal pivotally supporting said contact arm and a leaf spring including a blade portion and an arcuate-shaped base portion, the blade portion extending longitudinally of the contact arm and electrically and mechanically abutting the same so as to bias it into engagement with the said rotor and the said arcuate shaped base portion abutting said contact terminal and forming electrical contact therewith.

3 4- r v 2. A rotary switch as claimed in claim 1, wherein the References Cited arcuate-shaped portion of the said leaf spring is formed UNITED STATES PATENTS with an extension including a concavely curved portion disposed in overlying relation to a convexly curved part 3,351,956 5/1966 Rasor et of aid ca i 3,260,803 7/1966 Mitsuru 3. A rotary switch as claimed in claim 2, wherein a 5 3,299,225 1/1967 Heathportion of the said extension is bent to form a projection facing away from the blade portion directed towards a ROBERT SCHAEFER Pnmary Exammer recess in the side wall of the switch casing. I. R. SCOTT, Assistant Examiner 4. A rotary switch as claimed in claim 1, wherein the 10 blade portion is secured to the contact arm by a lug bent US. Cl. X.R.

out of the blade portion and engaging round an adjacent 153 166 portion of the contact arm. 7 

